Material containing polyreaction products for the coating layer of planar structures

ABSTRACT

The present invention relates to materials containing polyreaction products cured by UV radiation in presence of at least one UV initiator and/or electron radiation and/or IR radiation, planar structures based on renewable raw materials which contain these materials particularly in the coating layer, and methods of the production of said planar structures.

FIELD OF THE INVENTION

The present invention relates to materials containing polyreactionproducts, planar structures based on renewable raw materials whichcontain these materials particularly in the coating layer and covercoat, respectively, and methods of the production of said planarstructures.

Linoleum as an elastic floor covering based on renewable raw materialshas long been known. Due to its natural components linoleum has achieveda high value regarding construction-biological and ecological areas.Nevertheless, the production of linoleum coverings requires a thermaltreatment in the last method step, the so-called “ripening time”, whichtakes several weeks.

DE-A-41 35 664 teaches coating masses which are based on renewable rawmaterials and serve to coat planar textile structures or release paper.The coating masses consist of a combination of epoxidation products ofesters of unsaturated fatty acids and partial esters of polycarboxylicacids with polyether polyols as well as with a hydrophobing agent. Thesecoating masses are used to produce floor coverings. However, the factthat the uppermost layer of coatings produced in this manner is veryrough and non-transparent and exhibits a coloration caused by thethermal cross-linking is a disadvantage. Furthermore, the coatings ofthe back require a complicated production with rather expensiveseparating paper and have no foam and, therefore, are not comfortablewhen walked on. Furthermore, it turns out that the surface of thesecoverings is not sufficiently stain-repellent and not fully hardened.

BACKGROUND OF THE INVENTION

WO-96/15203 teaches coatable and, respectively, spreadable coatingmasses for the production of planar structures based on renewable rawmaterials. However, the production of these planar structures,particularly the coating layer and the wear layer, respectively, iscarried out by thermal cross-linking of the coating masses, whichresults in yellowing of the coating layer.

SUMMARY OF THE INVENTION

Thus, the problem underlying the present invention is to provide novelplanar structures based on renewable raw materials which do not requirethe time-intensive ripening time of linoleum coverings and substantiallydo not show yellowing of the coating layer and wear layer, respectively.Furthermore, these planar structures should have excellent materialproperties.

DETAILED DESCRIPTION OF THE INVENTION

This problem is solved by the embodiments characterized in the claims.In particular, there is provided a material containing polyreactionproducts wherein the polyreaction products are obtainable by reacting ofat least one di- or polycarboxylic acid or their derivatives or of amixture thereof with at least one epoxidation product of a carboxylicacid ester or with a mixture of these epoxidation products andsimultaneously or subsequent curing of the reaction product, wherein thereaction and/or curing is substantially carried out by

(a) UV radiation in presence of at least one UV initiator and/or

(b) electron radiation optionally in presence of at least one UVinitiator and/or

(c) IR radiation.

UV initiators used in the present invention may be radical or cationicUV initiators, or a mixture of said types of UV initiators. Preferredexamples of radical UV initiators are benzophenone, benzophenonederivatives, phosphine oxides, α-morpholino ketones, quinone, quinonederivatives or α-hydroxy ketones, or mixtures thereof. Preferredexamples of cationic UV initiators are triarylsulfonium salts which maybe of one type or a mixture of different triarylsulfonium salts, ordiaryliodonium salts, or mixtures thereof. Said UV initiators arepresent, for example, in an amount up to 8% by weight, preferably 0.1 to3% by weight, based on the amount of the material containingpolyreaction products.

In one embodiment of the present invention, besides the UV initiator, atleast one photosensitizer may be present, such as e.g. compounds basedon anthracene, perylene or thioxanthene-9-one, which is able to activatethe UV initiator and to enhance the effectiveness thereof, therebyreducing the concentration of the UV initiator. UV radiation employed inthe present invention is, generally, within the usual range, i.e. 200 nmto 380 nm. IR radiation employed in the present invention is, generally,within the usual range, for example, 760 nm to 0.5 mm.

The di- or polycarboxylic acids or their derivatives preferably containat least one double bond per molecule.

The dicarboxylic acid used can preferably be maleic acid, itaconic acid,fumaric acid, succinic acid, methylsuccinic acid, malic acid orfurandicarboxylic acid, or a mixture thereof containing at least two ofthese acids. The polycarboxylic acid used can preferably be acids withthree or more carboxylic acid groups such as e.g. citric acid andaconitic acid.

Anhydrides or partial esters or derivatives having at least one freecarboxylic acid group can be used as derivatives of di- orpolycarboxylic acids. The alcohol component of the partial esters is notsubject to any particular limitation; however, polyols such asdipropylene glycol, propane diols, butane diols, hexane diols, hexanetriols, glycerin or pentaerythrite, or a mixture thereof containing atleast two of these polyols are preferably used as alcohol component.

In an especially preferred embodiment, as a cross-linking agent, amixture of a partial ester of maleic acid anhydride and dipropyleneglycol is used together with citric acid, wherein the portion of citricacid is up to 50% by weight, more preferably up to 25% by weight, basedon the total amount of the cross-linking agent.

The epoxidation product preferably contains more than one epoxy groupper molecule. The following can be used with preference as epoxidationproduct of a carboxylic acid ester: Epoxidized linseed oil, epoxidizedsoybean oil, epoxidized castor oil, epoxidized rape-seed oil or vernoniaoil, or a mixture thereof containing at least two of these epoxidizedproducts. The previously defined alcohols of partial esters such as e.g.dipropylene glycol, propane diols, butane diols, hexane diols, hexanetriols or pentaerythrite, or a mixture thereof containing at least twoof these polyols can also be used as the alcohol component of thesecarboxylic acid esters. The carboxylic acid component is not subject toany particular limitation.

Furthermore, the material containing polyreaction products may containfurther at least one additive selected from the group consisting offillers, pigments for designing and patterning, respectively, expandingagents and/or foaming agents, hydrophobing agents and auxiliarysubstances.

The fillers are preferably wood dust, chalk, cork dust, barium sulfate,silicic acid, kaolin, lignin, cellulose, talcum, glass, textile fibersor glass fibers or plant fibers, cellulose fibers, polyester fibers ore.g. colored granulates and chips, respectively, made of the inventivematerial containing polyreaction products, or a mixture thereofcontaining at least two of these substances. Wood dust, chalk,cellulose, lignin or cork dust, or a mixture thereof containing at leasttwo of these substances are especially preferred as filler.

The following can be used by way of example as auxiliary substances:Tall oils, synthetic or natural resins such as e.g. balsamic resin,copals, hydrocarbon resins and/or siccatives such as e.g. compounds ofthe metals Al, Li, Ca, Fe, Mg, Mn, Pb, Zn, Zr, Ce or Co, or acombination thereof containing at least two of these compounds.

The invention is further directed to a planar structure composed of atleast one support layer (I) and of at least one coating layer (II) whichcomprises the material containing polyreaction products as definedabove, optionally an back layer (III) arranged under the support layer(I) and made of a chemically or mechanically foamed foam layer,optionally an compact or priming layer (IV) arranged between the supportlayer (I) and the coating layer (II) and/or between the support layer(I) and the back layer (III), optionally an chemically foamed foam layer(V) arranged under the coating layer (II), wherein the coating massesfor the layers (II), (III), (IV) and (V) contain a material containingpolyreaction products as defined above, with the proviso that the curingof the material containing polyreaction products contained in the layers(III), (IV) and (V) is at least partially carried out by:

(a) UV radiation in the presence of at least one UV initiator and/or

(b) electron radiation optionally in the presence of at least one UVinitiator and/or

(c) IR radiation and/or

(d) thermally,

wherein no UV initiators are required when curing by IR radiation orthermal curing of the layers (III), (IV) and (V).

The inventive planar structures, i.e. floor coverings or tiles, aremanufactured. such that a combination of the above defined di- orpolycarboxylic acids and their derivatives, respectively, andepoxidation products mixed in the weight ratio of 1:0.3 to 1:8,particularly 1:0.5 to 1:3, 1:0.6 to 1:1.2 and 1:1 to 1:4, fillers and,in the case of the mass for the coating layer, optionally hydrophobingagents, and in the case of the mass for a chemical foam, a foamingagent, and optionally a foam stabilizer for each foam compound, is mixedand processed to form a paste, and these pastes are then processed in aknown way to form multi-layer floor coverings. The coating mass for thecoating layer (II) contains preferably 7 to 44% by weight hydrophobingagent, based on the amount of the material containing polyreactionproducts.

The coat pastes for the planar structure according to the presentinvention all may contain greater quantities of filler, wherein,preferably, amounts from 10% by weight to 60% by weight, preferably 30%by weight, are used in the compact layer and 20 to 65% by weight,preferably 35% by weight, in the chemical foam, whereas only little,preferably no more than 10% by weight, e.g. 1 to 10% by weight, morepreferably no more than 5% by weight, filler are usually contained inthe compounds for the mechanical foam. All percentage particulars referto the total quantity of the material containing polyreaction products,when not specified to the contrary.

The coating layer (II) may be transparent or may have any desiredpattern by admixing of the additives as defined above such as cellulose.In case the coating layer is transparent, the coating mass for thecoating layer (II) contains preferably no more than 8% by weight, morepreferably no more than 2% by weight, fillers. Further, if the coatinglayer (II) is transparent, the layer lying therebelow can then beprinted on, and, thus, a printed planar structure is obtained that hashigh mechanical strength and extremely good dirt-repellant properties. Amulti-layer covering having a parquet pattern as well as enameled clothand synthetic leather or protective layers for glass can be mentioned asexamples of such an employment.

The coverings contain comparatively high proportions of additives,particularly mineral fillers from the group of chalk, barium sulfate,silicic acid, kaolin and talcum but optionally also comparatively highproportions of sawdust, cork dust, ground glass, cellulose, lignin,textile filaments or plant fibers, which may also be present in themixture, wherein the quantity of fillers in the overall floor coveringcan amount to up to 70% by weight, preferably 30 to 60% by weight in thecase of foam-free coverings, and preferably 40 to 60% by weight of theoverall floor covering in the case of floor coverings having chemicallyfoamed layers.

With respect to masses for the chemically foamed layers, the quantity offoaming agent lies in the standard range up to approximately 15% byweight, and other standard auxiliaries can amount, for example, up to15% by weight.

The floor coverings are preferably composed of three, four or fivelayers, for example, a simple structure built up of an optionallyprinted support such as paperboard, a coating layer and a protectivelayer, or a structure built up of a compact layer, an optional chemicalfoam layer, a transparent coating layer and a support layer and,optionally, a chemically foamed back layer, wherein the chemical foam,of course, can also be replaced by a mechanical foam or wherein bothtypes of foam can be present. When a chemically foamed layer (V) isarranged between the compact layer and the coating layer, this can bechemically embossed in a specific embodiment of the invention. Thischemically foamed layer (V) may also comprise the material containingpolyreaction products, preferably cured by UV radiation, as definedabove. To that end, a paste is applied on the compact layer. This pastecontains an expander and a kicker; what is meant by this are polyols,urea, zinc, lead or cadmium compounds, whereby ZnO is preferred. Theselower the decomposition temperature of the expander. The paste coat isthen crosslinked below the decomposition temperature of the expander. Inthe next fabrication stage, the coated paste is provided with arotogravure pattern. An inhibitor is added to the inks that should bedark and deep, respectively, in the finished covering. The inhibitorweakens the effect of the kicker or entirely cancels it, so that thedecomposition of the expander is shifted towards higher temperatures.Suitable substances having inhibitor effect are, for example,benzotriazol derivatives, trimellitic acid anhydride and the like.Various relief depths can be achieved by varying the quantity of addedinhibitor. A protective layer (VI) of polymers or, respectively,copolymerizates or waxes can then be arranged over this chemicallyfoamed layer with applied relief pattern and the coating layer lyingabove it. Examples of these unsaturated, curable lacquer systems arepolyacrylates, polymethacrylates, polyurethanes and mixtures thereof.However, carnauba wax can also be utilized. The protective layer shouldbe manufactured from (co)polymers compatible with the coating layer.

It surprisingly turned out that, when curing the coating masses for thecoating layer (II) by UV radiation, electron radiation and IR radiation,respectively, the planar structures according to the present inventionsubstantially do not show coloration, particular yellowing, of thecoating layer and wear layer, respectively.

Further subject matter of the present invention relates to a method offabricating the aforementioned planar structure, wherein at least thecoating layer (II) is substantially cured by UV radiation in thepresence of at least one UV initiator as defined above, which iscompounded into the mixture for the layer to be cured, and/or byelectron radiation optionally in presence of at least one UV initiatorand/or IR radiation.

In particular, this is a matter of a continuous process that, similar toCV manufacture, successively describes an overall structure of a floorcovering with different pastes. As already mentioned, such a method canalso comprise foaming, particularly chemical foaming, and leads to acovering that can be printed.

In one embodiment of the method of the present invention, the coatinglayer (II) is partially cured by UV radiation, followed by embossing thepartially cured coating layer (II) and then curing the embossed,partially cured coating layer (II) by UV radiation and/or electronradiation and/or IR radiation and/or thermally.

The manufacture of the covering ensues, for example, in that theconstituents are mixed to form a paste, applied in an appropriatethickness on a web with coating devices, optionally foamed andsolidified in a known way. Layers containing foaming agent and layersfree of foaming agent can also be unified to form a web and can befoamed and solidified simultaneously or in successive steps.

As auxiliary substances, acrylates such as, for example, poly(methylmethacrylate) may be worked into the wear layer in order to improve theadhesion between the applied ultraviolet lacquer and the wear layer,i.e. the coating layer. Linseed oil in amounts of up to 15% by weightcan also be contained in the coating layer as an auxiliary.

1 to 5% by weight of azodicarboxylic acid amide or sulfohydrazides canbe employed as foaming agent (expander) for the back layer, wherein, inparticular, 3% by weight of foaming agent are preferred. As alreadymentioned above, kickers can also be utilized in the chemical embossingprocess in order to lower the decomposition temperature of the foamingagent. In particular, zinc oxide is utilized here according to thepresent invention.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a preferred embodiment of the planar structures accordingto the present invention composed of a support layer (I) which has apriming layer (IV) on both sides thereof, a back layer (III) arrangedtherebelow, a chemically foamed foam layer (V) arranged on the priminglayer lying above, a coating layer (II) arranged above and a protectivelayer (VI) arranged above the coating layer.

EXAMPLES

In another embodiment of the present invention, the material containingpolyreaction products according to the present invention can be used asa back surface coating for textile planar structures such as floorcoverings.

The present invention is explained in detail in the following examplesshowing UV cross-linking of the coating layer in preferred ranges of theused constituents.

Example 1

51 g of epoxidized linseed oil are mixed with 1.1 g of a cationicphotoinitiator based on triarylsulfonium salt, 2 g of highly dispersesilicic acid, 3 g of poly(methyl methacrylate) and 2 g of linseed oil.Then, 48 g of a partial ester of maleic acid anhydride and dipropyleneglycol are added and the mixture is compounded in a commerciallyavailable laboratory dissolver.

After degassing of the mixture the mass is blade coated onto apaperboard support and cured by UV light having a wavelength of 295 nmto 400 nm. The coating layer thus obtained is colourless andnon-adhesive (non-sticky).

Example 2

51 g of epoxidized linseed oil are mixed with 0.8 g of a cationicphotoinid on a triarylsulfonium salt, 2 g of highly disperse silicicacid, 3 g of poly)methacrylate) and 2 g of linseed oil. Then, 15 g of a25% by weight solution of citric acid in a partial ester of maleic acidanhydride and dipropylene glycol are added and the mixture is compoundedin a commercially available laboratory dissolver.

After degassing of the mixture the mass is blade coated onto a paperportboard support and cured by UV light having a wavelength of 295 nm to 400nm. The coating layer thus obtained is colourless and non-adhesive(non-sticky).

What is claimed is:
 1. A method of fabricating a planar structure havingat least one support layer (I) and at least one coating layer (II),optionally a back layer (III) arranged under the support layer (I) andmade of a chemically or mechanically foamed foam layer, optionally acompact or priming layer (IV) arrange between the support layer (I) andthe coating layer (II) and/or between the support layer (I) and the backlayer (III), optionally a chemically foamed foam layer (V) arrangedunder the coating layer (II), wherein the coating masses for the layers(II), (III), (IV) and (V) contain a material containing polyreactionproducts being obtainable by reacting of at least one di- orpolycarboxylic acid or their derivatives or of a mixture thereof with atleast one epoxidation product of a carboxylic acid ester or with amixture of these epoxidation products, wherein at least the coatinglayer (II) is substantially cured by UV radiation in the presence of atleast one UV initiator which is compounded into the mixture for thelayer to be cured, and/or by electron radiation.
 2. The method accordingto claim 1, wherein the coating layer (II) is partially cured by UVradiation, followed by embossing the partially cured coating layer (II)and then curing the embossed, partially cured coating layer (II) by UVradiation and/or electron radiation and/or IR radiation and/orthermally.
 3. The method according to claim 3, wherein the UV initiatoris a radical or cationic UV initiator or a mixture thereof.
 4. Themethod according to claim 3, wherein the radical UV initiator isbenzophenone, a benzophenone derivative, a phosphine oxide, aα-morpholino ketone, quinone, a quinone derivative or a α-hydroxyketone, or a mixture thereof.
 5. The method according to claim 3,wherein the cationic UV initiator is a triarylsulfonium salt or amixture of different triaiylsulfonium salts, or a diaryliodonium salt ora mixture thereof.
 6. The method according to claim 1, wherein the UVinitiator is present in an amount up to 8% by weight, based on theamount of the material containing polyreaction products.
 7. The methodaccording to claim 1, wherein the material containing polyreactionproducts further comprises at least one additive selected from the groupconsisting of fillers, pigments, expanding agents, hydrophobing agentsand auxiliary substances.
 8. The method according to claim 1, whereinthe dicarboxylic acid in the material containing polyreaction productsis maleic acid, itaconic acid, fumaric acid, succinic acid,methylsuccinic acid, malic acid or furandicarboxylic acid, or a mixturethereof containing at least two of these acids.
 9. The method accordingto claim 1, wherein the polycarboxylic acid in the material containingpolyreaction products is selected from citric acid or aconitic acid. 10.The method according to claim 1, wherein the derivative of the di- orpolycarboxylic acid in the material containing polyreaction products isan anhydride or a partial ester.
 11. The method according to claim 10,wherein the alcohol component of the partial ester is a polyol.
 12. Themethod according to claim 11, wherein the polyol is dipropylene glycol,a propane diol, a butane diol, a hexane diol, a hexane triol, glycerinor pentaerythrite, or a mixture thereof containing at least two of thesepolyols.
 13. The method according to claim 1, wherein the mixture of atleast one di- or polycarboxylic acid or the derivatives thereof is amixture of a partial ester of maleic acid anhydride and dipropyleneglycol with citric acid.
 14. The method according to claim 1, whereinthe epoxidation product of a carboxylic acid ester contains more thanone epoxy group per molecule.
 15. The method according to claim 1,wherein the epoxidation product of a carboxylic acid ester is epoxidizedlinseed oil, epoxidized soybean oil, epoxidized castor oil, epoxidizedrape-seed oil or vernonia oil or a mixture thereof containing at leasttwo of these epoxidized products.
 16. The method according to claim 7,wherein the filler is wood dust, chalk, cellulose, lignin or cork dust,or a mixture thereof containing at least two of these substances. 17.The method according to claim 7, wherein the auxiliary substance isselected from the group consisting of tall oils, synthetic or naturalresins and siccatives.
 18. The method according to claim 1, wherein thecoating layer (II) is transparent.
 19. The method according to claim 1,wherein a chemical foam layer (V) for chemical embossing is arrangedunder the coating layer (II).
 20. The method according to claim 1,wherein a protective layer (VI) made of unsaturated curable lacquersystem is arranged above the coating layer (II), wherein the polymers orcopolymers for the lacquer systems are selected from the groupconsisting of polyacrylates, poly(meth)acrylates, polyurethanes, andmixtures thereof.
 21. The method according to claim 1, wherein thecoating mass for the coating layer (II) further contains a hydrophobingagent.
 22. The method according to claim 1, wherein the coating mass forthe coating layer (II) contains no more than 8% by weight fillers. 23.The method according to claim 1, wherein the coating mass for thecompact or priming layer (IV) contains 10 to 60% by weight fillers,based on the amount of the material containing polyreaction products.24. The method according to claim 1, wherein the coating mass for thechemically foamed foam layer (V) contains 20 to 65% by weight fillers,based on the amount of the material containing polyreaction products.25. The method according to claim 1, wherein the coating mass for themechanically foamed foam layer (V) contains up to 10% by weight fillers,based on the amount of the material containing polyreaction products.